2 gang switch live when dead

[eckersecker]

Recently opened a 2 gang switch on a landing. Had knocked out the breaker for the lights on the landing. Waved my volt stick in there and the other gang was still live as it supplied the next stairs up off a different circuit. Is this acceptable in the regs ? It seems to be a bit dangerous having two supplies into one switch. If I was doing a PIR would this need coding?

Thanks.

 

[Adam W]

To my recollection it's fine as long as they're on the same phase.
I get your point though - I'd probably label it in some way to avoid confusion (or worse).

 

[Deleted member 9648]

It's quite usual and ok to have more than one circuit in a switch......thats why there are safe isolation proceedures.

 

[1billy wiz]

strapper's.

 

[eckersecker]

Thanks to novusparkus and wirepuller.

 

[chiplard]

Would the switch not need to be identified as having 2 supplies?

I was always under the impression that this was bad practice. Especially as home owners can and do change switches as and when without competency.

 

[eckersecker]

Is that more than one strapper or something belonging to a strapper?

 

[Deleted member 19807]

Would the switch not need to be identified as having 2 supplies?

I was always under the impression that this was bad practice. Especially as home owners can and do change switches as and when without competency.

this is standard practice in domestic wiring and should be expected by anyone carrying out electrical work. If the board has up & down lights & 2 way switching on stairs then you will find this at both top and bottom switches.

 

[chiplard]

I would disagree. Standard practice would be to have either the down light on the upstairs circuit or visa versa.

Please read 514.1.1 and 514.11.1 and also 537.2.1.3 for clarification regarding identification.

 

[1billy wiz]

only the common of the strapper is live was the colours red,yellow,blue??

 

[chiplard]

And in my opinion it would be a code 2

 

[derek preece]

I would disagree. Standard practice would be to have either the down light on the upstairs circuit or visa versa.

Please read 514.1.1 and 514.11.1 and also 537.2.1.3 for clarification regarding identification.

If the stair well lights are fed from the ground floor and has a two gang switch on the top floor (with the other switch controlling a seperate circuit with supply from the upstairs circuit) where would you put the warning (in a domestic senario) or do you think that the top floor 2way switch should be single gang and any other circuits fed from a different CB should have a completely seperate switch?

 

[chiplard]

As the regs state there must be identification on the switch to indicate more than one supply. If the upstairs 2G switch was to control another light ( from the downstairs circuit ) then i would identify the fact at the CU or put 2 separate switches in. Either that or put a notice on the 2G switch upstairs that 2 circuits are controlled from that switch ( which isn't going to happen as it doesn't look very nice!! ).

 

[Deleted member 19807]

I would disagree. Standard practice would be to have either the down light on the upstairs circuit or visa versa.

Please read 514.1.1 and 514.11.1 and also 537.2.1.3 for clarification regarding identification.

I disagree, 514.1.1 relates to the operation of switch gear not isolation, 514.11.1, it can be isolated from a sigle device, the main switch.

 

[Deleted member 19807]

also if you feed them from the same mcb then in the case of a fault you will loose both lights over the stairs.

 

[chiplard]

I disagree, 514.1.1 relates to the operation of switch gear not isolation, 514.11.1, it can be isolated from a sigle device, the main switch.

Having re-read 514.1.1 I would agree with you.

You are right with regards to 514.11.1 but it also states that the location of each isolator shall be identified unless there is no possibility of confusion.

What is the problem with losing both lights over the stairs?

 

[Des 56]

Safe isolation is the major player with this debate
If a person islolates a single mcb and follows safe isolation procedure, he will soon find out that it needs 2 mcbs isolated
So in theory,no danger can exist,if in doubt,a person working on the switch should do as hifly suggests, and switch off the main switch

There is nothing wrong with 2 seperately supplied circuits in one switch box

 

[Deleted member 19807]

What is the problem with losing both lights over the stairs?


314.1

 

[chiplard]

Safe isolation is the major player with this debate
If a person islolates a single mcb and follows safe isolation procedure, he will soon find out that it needs 2 mcbs isolated
So in theory,no danger can exist,if in doubt,a person working on the switch should do as hifly suggests, and switch off the main switch

There is nothing wrong with 2 seperately supplied circuits in one switch box

How would he find out? A sparky with a meter would. But a home owner?

I agree there is nothing wrong with 2 separately supplied circuits in one switch as long as it is identified correctly, as stated in the BRB.

 

[chiplard]

What is the problem with losing both lights over the stairs?


314.1

Would you put every room on its own MCB then?